Eraser



March 7, 1950 c. J. SCHREIBER ERASER Filed Sept. 13, 1948 R O T N r e V mm 8 r h c 8 lm s. e H a h c ATTORNEY$.

Patented Mar. 7, 1950 UNITED STATES PATENT OFFICE This invention relates to erasers and has for its primary object to provide structural improvements which will increase the erasing efliciency of an eraser, decreasing the time and effort required and cleaner in its operation.

Heretofore attempts have been made to provide erasers with separated elements, slits, apertures or grooves and even erasive layers joined by different grades of rubber or adhesives, as Well as other arrangements, none of which operate in the 'slits in the next adjacent rows, so that the ends of the eraser, as they wear away, always present a number of inner sharp edges throughout the length of the eraser.

The slitted eraser in accordance with my invention has numerous advantages over the monolithic type including erasers of the types above mentioned. Whereas the common eraser is almost constantly worn to a curved smooth surface, my slitted eraser constantly has a surface which has quite sharp edges and the connecting uncut portions between the slits maintain the eraser in a substantially solid condition during use. The sharp edges provided by the slits make a clean erasing job without cutting into the erased surface any more than does a comparable eraser without the slits; thus, due to the sharp edges erasing is made easier and quicker. Since less time and energy is spent in erasing, the erased surface suffers less damage. Therefore, if the erasing surface is to be kept in a nearly perfect condition a slitted eraser of softer quality can be used to perform the same job that would ordinarily require a coarser eraser of the common type.

The slitted eraser in accordance with my invention is a saving in any drafting room since in a drafting room the common eraser is usually cut down with a knife to a fairly sharp edge by the draftsman. This is uneconomical as quite a bit of the eraser is in this manner cut away and discarded. The slitted eraser, therefore, is more economical as it is used entirely for erasing with out being cut up and sharpened, and less time is spent by the user in making a clean erasing job.

Another important advantage of my slitted eraser as compared with the common eraser is: the common eraser has a great tendency to smear the erased surface because the lead from the pencil mark sticks to the eraser and is dragged across the erasing surface of the paper, leaving a smudge. This necessitates cleaning the eraser by rubbing it on another surface until the pencil lead has been rubbed off. Such trouble is avoided by the use of a slitted eraser in accordance with my invention as the slits collect the pencil lead along with parts of the eraser which wear off during the process of erasing. In this way the lead, or graphite, is collected by the eraser itself and does not smudge the paper. In using the slitted eraser one can actually feel how much better it takes on the lead marks than does the common type eraser of the same quality of rubber.

Further, slitting of the eraser in accordance with my invention does not weaken it to any noticeable extent because in gripping the eraser the user automatically compresses the slits which gives the eraser a monolithic tendency equal to the toughness of a comparable eraser not slitted.

Still further objects, details and advantages of my invention will appear in the following description of highly satisfactory embodiments of slitted erasers in conjunction with the accompanying drawings illustrating the same and forming a part of this specification.

In the drawings;

Fig. 1 is a perspective View of an eraser slitted in accordance with my invention.

Fig. 2 is a plan view thereof.

Fig. 3 is a sectional view taken on line 3-3 of Fi 2.

Fig. 4 is a perspective view of a simplified construction to illustrate the effectiveness of my invention.

Fig. 5 is a plan view and Fig. 6 a transverse sectional view taken on line 66 of Fig. 5 of a circular typewriter type of eraser incorporating slits in accordance with my invention.

Referring to the drawings, in general the eraser 5 illustrated is of the usual long or monolithic type of rectangular cross-section and having oppositely tapered ends 6, as one type of eraser to which my invention is adaptable. Of course in use such tapered ends wear away, as well known, and the physical contour of the eraser is thus changed. Thus, while in the preferred form an elongated eraser is illustrated, other forms are adaptable to receive the slits as shown and operate in the same manner.

In accordance with my invention I provide the eraser 5 with a plurality of spaced parallel rows I of slits 8 and 9, the slits 8 and 9 of alternate rows being arranged in overlapping relationship with respect to each other. In such an eraser 5, as shown, the arranement of five or six rows 1 with slits B and 9 each about an eighth inch long and spaced about a sixteenth inch apart endwise is highly practical and the eraser when held for use has substantially the same rigidity as a solid eraser. It will be seen that the slits either 8 or 9 always extend through the end of the eraser as it wears away, and thus present the sharp cleaning edges and pockets substantially normal to the cleaning surface of the eraser for picking up the erasure dirt.

Slits 8 and 9 may be and preferably are formed through eraser 5 by means of a knife blade type of punch. The slits thus are knife blade cuts without removing any of the body of the erasive material preferably, as distinguished from slots wherein part of the material is removed or formed with the side walls spaced-apart. Such slits, while the side walls are normally in engagement, do

provide pockets or holding devices which pick up the refuse resulting in an erasing operation. By means of a multi-blade knife the slits can be -made in an eraser by a single stroke, using a punch press of the usual type, or a rotary type cutter may be employed, neither of which cutting devices is claimed in the present application.

A simplified construction in accordance with my invention to illustrate its efiectiveness may be produced by taking a monolithic type of soft rubber pencil eraser it! and cutting three or four slits i 5 about an eighth inch deep into its end i2 as shown in Fig. 4the same as end slits 8 in eraser 5 in Fig. 1-without slitting the other end l3. By erasing pencil marks, hard, soft or very soft, on a sheet of paper, with the slitted end II, the results can be compared with the results using the other solid end E3 of eraser H3. The results and advantages of such a slitted eraser will be fully realized.

It will be seen that when applied to a soft rubber monolithic type of eraser the slitted eraser in accordance with my invention is particularly adapted for erasing pencil marks. Also ink erasing with the same may be facilitated, though such slits may be applied to other types of erasers including ink erasers, rubber containing certain amonuts of abrasive material, or other erasive material in accordance with my invention with improved results in operation.

The slitting of erasers in accordance with my invention does not only improve the performance of pencil and ink erasers where the slits are advantageous, but as shown in Figs. 5 and 6 slits I 4 are arranged in overlapping relationship in radial rows 15 in a circular type of typewriter eraser [6. In this arrangement the rows [5 are radial rather than parallel but the slits are always substantially normal to the erasing surface to operate to the same advantage. Likewise such slits perform to advantage in artists gum erasers noting that they present the sharp cleaning edges and pockets or recesses for picking up the small particles of dirt.

Having described several forms of erasers incorporating my invention, what I claim and desire to secure by Letters Patent is:

1. An eraser comprising a body of erasing material having spaced rows of short slits extending laterally through the erasing material so as to be normal to the erasing area of the eraser with the side walls of the slits normally in engagement providing a series of sharp edges along the erasing area of the eraser and pockets which pick up and engage erasure refuse formed during an erasing operation and with the slits spaced apart enclwise of the rows, the slits of each row being substantially parallel with and in overlapping relationship with respect to the slits of adjacent rows so that the eraser will be substantially rigid but the erasing area will constantly present open slits as the eraser is worn away at the erasing area in use.

2. An eraser comprising a monolithic type of rubber erasing material of substantially rectangular cross-section throughout its length, said eraser characterized by having a plurality of parallel rows of substantially equally spaced slits extending through from face to face of the eraser with the slits of each row in an overlapping relationship with respect to the slits of the adjacent rows.

CHARLES J. SCHREIBER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 230,700 Gaylord Aug. 3, 1880 2,330,954 Cotera Oct. 5, 1943 

